Method decrypt

StegaPy/util/crypto_util.py:87–121

解密数据

(self, data)

            raise Exception(f"加密失败: {str(e)}")
    
    def decrypt(self, data):
        """解密数据"""
        try:
            # 读取IV长度
            iv_len = data[0]
            # 读取IV
            iv = data[1:1+iv_len]
            # 读取密文
            ciphertext = data[1+iv_len:]
            
            # 创建解密器
            if self.algorithm.startswith('AES'):
                cipher = Cipher(
                    algorithms.AES(self.key),
                    modes.CBC(iv),
                    backend=default_backend()
                )
            else:
                raise ValueError(f"不支持的算法: {self.algorithm}")
            
            decryptor = cipher.decryptor()
            
            # 解密
            padded_data = decryptor.update(ciphertext) + decryptor.finalize()
            
            # 去除填充
            unpadder = padding.PKCS7(128).unpadder()
            plaintext = unpadder.update(padded_data)
            plaintext += unpadder.finalize()
            
            return plaintext
        except Exception as e:
            if "Bad" in str(e) or "Invalid" in str(e):
                raise Exception("密码错误或数据损坏")
            raise Exception(f"解密失败: {str(e)}")